Sliding contact brushes



Nov. 17, 1964 R. J. BEAULIEU 3,l57,770

SLIDING CONTACT BRUSHES Filed Oct. 11. 1961 2 Sheets-Sheet 1 Roland JBeau/eu INVENTOR.

Nov. 17, 1964 R. J. BEAULIEU SLIDING CONTACT BRUSHES 2 Sheets-Sheet 2Filed Oct. ll. 1961 Fig.6

Fig. 5

Roland J Beau/ieu IN VENTOR. do@...

BY EMA:

United States Patent O 3,157,770 SLIDENG CONTACT BRUSEES Roland J.Eeaulieu, 531 hi'ontgonery St, Fall River, Mase. Fiiel Oct. il, 1961,ser. No., %4,478 S Ciams. (Ci. %lil-166) This invention relates toelectrical conducting devices, and more particularly to an electricalbrush for conducting electrical current or impulses between relativelymoving members.

it is the primary object of this invention to provide an electricalbrush which has the characteristics of flcxing very rapidly and at thesame time always making an eX- cellent contact with the relativelymoving member with which it has rubbing contact.

It is still another object of the invcntion to provide a brush which isparticularly adapted to be made in eX- tremely small sizes, however, itsdesign permits it to be made in any size desirec.

It is still another object of the invention to provide an electric brushwhich has built-in guide means to prevent its rubbing surface frommoving laterally and maintains the direction of movement of this surfacegenerally normal to the surface with which the brush Contacts.

It is another object of the invention to provide an electric brush whichis practically immune from undesirable effects caused by vibration orShock.

It is still another object of the invention to provide a brush betweentwo reiatively movable surfaces which creates a minimum'amount of torqueor drag between the surfaces.

It s still another object of the invention to provide an electricalbrush that has an extremely long life and produces a minimum of noise inoperation.

It is still another object of the invention to provide an electricalbrush which permits exceptional high or low speed operation of thedevice in which it is used.

It is still another object of the invention to provide an electric brushwhich has buil^-in vibration dampem'ng means to reduce or eliminatebounce or chatter.

It is yet another object of the invention to provide an electric brushwhich is not aitected by local changes in temperature and pressure.

It is still another object of the invention to provide an electricalbrush which is equally effective regardless of the direction of movementof the surfaces between which it is used.

Briefiy, the invention comprises a resilient brush adapted to be used inrotary switches, analogue converters, motors, digitalizers, telemeteringdevices, etc.

It is still yet another object of the invention to provide an electronicbrush which is relatively simple in design, economical to manuiacture,requires no maintenance and is durable and long lasting in use.

These together with other objects and advantages which will becomesubsequentiy apparent reside in the details oi` Construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

FIGURE 1 is a perspective View showing my brush mounted between tworelatively rotating surfaces with parts broken away;

FIGURE 2 is an enlarged cross sectional view taken substantialiy on theplane of line 2-2 of FIGURE l;

FIGURE 3 is a perspective view of the brush assembly shown in FIGURES 1and 2;

FIGURE 4- is a vertical cross sectonal View taken substantially on theplane of line 4-4 of PIGURE 3;

FIGURE 5 is a perspective view showing a pair of modified forms of mybrushes mounted on an electrical conducting surface;

FIGURE 6 is a perspcctive View showing a third modified form of myinvention;

FIGURE 7 is a perspective view showing a fourth modified form of myinvention; and

FIGURE 8 is a vertical cross sectional view taken substantially on theplane of line 8 8 in FIGURE 6.

As shown in FIGURES i through 3, one of my brush assemblies 16) ismounted between two relatively rotating discs 12 and 14. These discs mayconstitute the components of a Converter or commutator for example.

Disc 12 comprises a lower plate 16 formed of conductive material Securedto an upper plate 13 formed of an insulating material. Disc 14 iscomposed of a conductive material, but has a plurality of non-conductinginserts Z set into its upper face in a circular pattern concentric aboutthe axis of the disc.

he brush assembly il@ comprises two opposing spring elements 22 and 24which are mirror images of one another and are the same size and shape.Brushes are preferably composed of a resilient metal wire having goodconductive characteristics such as some of the precious metals.

Each of the spring elements 22 and 24 comprises an elongatedsubstantially straight mounting portion 26 and a cantiievered arm 23connected by means of a coiled helical portion 39. The helical portion3@ forms a torsional spring between the portion 26 and arm 23.

The portion 26 is approximately twice the length of the arm 28 and thecentral portion of the portion 26 is bulged toward the arm 23 to form asemi-circular ring or hurnp 32. In a similar manner, the arm 28 also hasa bulge formed therein which produces a semi-circular ring or hump .34projecting away from the portion 26.

In the specific application illustrated in FIGURES 1 through 4, thebrush assernbly 10 is Secured to the lower surface or" plate te byconventional means such as solder 36'. T he solder 36' maintains thelegs spaced in parallel relationship to each other in such a manner thatthe portions 25, the arms 28 and the axes of the coil springs 30 aresubstantially parallel to the surface of plate 16. Each spring 22 and2.4 is positioned as close to one another as permitted by the spacingtherebetween caused by the coils of coil spring 30.

A tubular member 36 is inserted between the humps 32 and the surface ofplate 16, and a solid cylindrical member 38 is inserted through the coilspring 30. Members 35 and 38 are preferably formed of silicone rubber.They may be held in position by friction or friction in conjunction withcement.

In operation, the relatively rotating discs 12 and 14 are spaced apartso as to form a space 4@ therebetween. The outer central portions of thesemi-circular rings or humps 34 have surfaces at 42 which act as brushcontact surfaces. Due to the spacing between the plates or discs 12 andM, brush surfaces 42 contact the opposing surfaces of the dsc 14 wherebythe disc 14 forces the arms 28 inwardly between the humps 32 as shown inFIGURE 2. The arms 28 are of sufcient length to reach to at least thecentral portions of the humps 32. When the discs 12 and M are rotatedrelative to one another, the brush surface 42 in conjunction with theremainder of the brush assembly conducts current between the plate 16and the inserts 20 when the surfaces 42 are contacting the inserts asillustrated in FGURE 2. Due to irregularities in the surfaces of theinserts 2@ and discs 14, the surfaces 14 and arms 28 will be caused tobe moved toward and away from the plate 116 as the disc 14 rotates.However, by Contacting and ccmpressing the rubber tubular member 36, themovement and vibration of the arms will be dampened. Also, as the arms23 move in and out in relation to the humps 32, coil spring 3% will windand unwind thereby creating a friction on the surface of the cylindricalmember 38 thereby further dampening vibration.

Since the extreme outer ends of the arms 28 are maintained between thehumps 32, the arms'are positively prevented from moving radiallyoutwardly with respect to the axis of discs 12 and 14.

In the modification shown in FIGURE 5, the brush assembly 44 issubstantially identical to that form shown in FIGURE 3, and consequentlysimilar parts havebeen given identical reference numerals. However, inthe form shown in FIGURE 5 the tubular member 36 and cylindrical member38 have been omitted. Also, the pair of adjacent humps 32 are slightlycanted or sloped so thattheir central portions 33 are spaced sufficientdistance apart to receive adjacent ends of the arms 28, however, the'ings or humps 32 converge together in a direction away from the centralportions 33 and toward the junctions 35 where the humps terminate.Therefore, the rings or humps 32 are spaced substantially closertogether at 35 than they are at 33 thus causing the extreme outer endsof the arms 28 to frictionally contact the inner surfaces of the humps32 When the arms are pressed downwardly between the humps.

Therefore, it is apparent that when the outer ends of the arms 28 areforced between the humps 32 to spread them apart, the friction betweenthe arms and humps function as a means for dampening vibration in thebrush assembly.

In the modification shown in FIGURE 6 two brush assemblies 44 aremounted in diametrical opposed relationship on a disc 12. These brushassemblies 44 are identical to the brush assemblies 46 shown in FIGURE 5eX- cept that one half of the brush assembly has been omitted.

In this particular arrangement, the humps or rings 32' will only preventlateral movement of the arm 23' in one direction, preferably theradially outward direction.

In the form shown in FIGURE 7, the brush assembly 48 is identical tothat form shown in FIGURE 6 except the humps 34 have been omitted andthe arms 28' are therefore straight. A rectangular brush member 59 ismounted on the outer surfaces of these arms and Secured thereto byconventional means. Brush member 50 has a concave surface 52 which isparticularly adapted for contacting the convex surfaces of commutatorssuch as those used in conventional motors and generators.

Normally, the various brush assemblies illustrated will be of a verysmall size only a fraction of the sizes illustrated in the drawings, forexample, it has been found that in electronic converters, brushes whichare three-eighths of an inch long by one-sixteenth inch high byone-thirtysecond of an inch wide perform very satisfactorily.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact Construction and operation shown anddescribed,

and accordingly all suitable modifications and equivalents may beresorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

-1. An electrical brush assembly composed of conductive material forconducting current between 'elatively rotating surfaces comprising abase adapted to be connected to one of the surfaces, a member having acontact surface for engaging and sliding on another of the surfaces,resilient means connecting the member to the base, said resilient meanscomprsing a coil spring which telescopcally receives and retains aresilient cylindrical member.

2. An electrical brush assembly composed of a conductive material forconducting current between relatively rotating surfaces comprising abase connected to one of said surfaces including a pair of parallel finewires having humps intermediate the ends thereof, a pair of parallelfine wire members having contact surfaces for engaging and sliding onanother of said surfaces terminating over said base wires adjacent saidhumps, resilient means connecting said members to the base wires at oneend thereof normally urging said members away from said humps, saidcontact surfaces located on the sides of the members opposite the base,the terminal portion of said members being latera'lly confined by saidhumps when said members and base are urged together by said surfaces.

3. A device as defined in claim 2 wherein the humps have divergingopposing side surfaces, the ends of said members adapted to be forcedbetween and friction-aily engaged by said side surfaces.

4. A device as defined in claim 2 wherein said htunp's are verticallyspaced from said one surface to define a recess, a resilient tubetelescoped within said recess, the terminal portions of said membersadapted to contact and compress said tube in operation for clampingvibrations in said brush. c

S. An electrical brush assembly composed of a conductive material forconducting current between relatively rotating surfaces comprising abase connected to one of said surfaces including a fine wire having ahump intermediate the ends thereof, a fine wire member having a contactsurface for engaging and 'sliding on another of said surface terminatingover said base wire adjacent said hump, resilient means connecting saidmembers to the base wire at one end thereof normally urging said memberaway from said hump, said contact surface located on the side of themember opposite the base, the 'terminal portion of said member beinglaterally confined by said hump in at least one direction when saidmember and base are urged together by said surfaces.

References Cited in the file of this patent UNITED STATES PATENTSZablocki Dec; 19, 1961

1. AN ELECTRICAL BRUSH ASSEMBLY COMPOSED OF CONDUCTIVE MATERIAL FORCONDUCTING CURRENT BETWEEN RELATIVELY ROTATING SURFACES COMPRISING ABASE ADAPTED TO BE CONNECTED TO ONE OF THE SURFACES, A MEMBER HAVING ACONTACT SURFACE FOR ENGAGING AND SLIDING ON ANOTHER OF THE SURFACES,RESILIENT MEANS CONNECTING THE MEMBER TO THE BASE, SAID RESILIENT MEANSCOMPRISIG A COIL SPRING WHICH TELESCOPICALLY RECEIVES AND RETAINS ARESILIENT CYLINDRICAL MEMBER.